Merge branch 'work_on_demos' into 'NIFTy_4'

demos/Wiener_Filter.ipynb

demos/paper_demos/cartesian_wiener_filter.py

demos/paper_demos/wiener_filter.py

demos/wiener_filter_easy.py

demos/wiener_filter_via_curvature.py

demos/wiener_filter_via_hamiltonian.py

nifty4/library/critical_power_energy.py

nifty4/library/noise_energy.py

nifty4/library/nonlinear_power_energy.py

nifty4/library/wiener_filter_curvature.py

nifty4/operators/diagonal_operator.py

nifty4/operators/scaling_operator.py

nifty4/probing/utils.py